Violet cotton-dye and process of making same.



NrTEn STATES PATENT OFFICE.

ROBERT DIQMUTH, OF ELBERFELD, GERMANY, ASSIGN OR TO THE FARBEN- FABRIKENOF ELBERFELD COMPANY, OF NEW-YORK, N. Y.

VIOLET COTTON-DYE AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 656,631, dated August28, 1900.

Application filed June 15, 1899. Serial No. 720.670- (Specimens) T0 (ZZZwhom it may concern.-

Be it known that I, ROBERT DEMUTH, doctor of philosophy and chemist, ofElberfeld, Germany, (assignor to the FARBENFABRIKEN OF ELBERFELDCOMPANY, of New York,) have invented a new and useful Improvement in theManufacture of Violet Cotton-D yes; and I do hereby declare thefollowing to be an exact and clear description thereof.

My invention relates to the production of a new class of violetcotton-dyestuffs by subjecting at elevated temperatures amido-LS-dioxynaphthalene sulfo-acids or salts thereof to the action of alkalinesulfid-carrying compounds in the presence of zinc, (using eithermetallic zinc, such as zinc dust, or any zinc compound.) According to myresearches, in place of the said amido-l. S-dioxynaphthalenesulfo-acidsall those substances (such as nitroso-l. S-dioxynaphthalene sulfo-acids,the azo coloring-matters obtainable from 1.8- dioxynaphthalenesulfoacids by the combination with diazotized amido compounds, or the like,)which under the influence of the alkaline sulfid-carrying compounds arefirst transformed into amido-1.8 dioxynaphthalenesulfoacids can also beused. Naturally I need not specifically claim the use of thesesubstances, as they by the reducing action of the alkalinesulfid-carrying compounds are first converted into.amido-1.8-dioxynaphthalenesulfoaeids, and the amido acids thus formedsubsequently yield the final dyestuffs.

The coloring-matters produced by means of this new process can bedirectly employed for dyeing purposes. They form blackish powderymasses, for the greatest part soluble in hot water, in hot dilutesoda-lye, in hot dilute sodium carbonate solution, and in concentratedsulfuric acid (66 Baum) with a reddish-vio1et color. From theirsolutions in water they are precipitated again by the addition of dilutemineral acids, sulfureted hydrogen being set free at the same time. Theydye unmordanted cotton in boiling baths containing common salt andsodium carbonate violet shades, which withstand the action of alkaliesand are sufficiently fast to the action of light.

In order to carry out my process practically, I can proceed'as followswithout limiting myself to the details given. The parts are by weight.Thirty parts of nitroso-LS- dioxynaphthalene-2. l-disulfo-acid are mixedwith twenty parts of water. After the addition of eighty-two parts ofsoda-lye (containing thirty per cent. NaOI-I) twenty parts of dry zincchlorid are stirred into the liquid mixture. Stirring is continued forsome time, and subsequently sixty-six parts of dry sodium sulfid andsixty parts of flowers of sulfur are added. The resulting mixture isslowly heated in an open iron vessel, profitably by means of a metallicbath, to 200 centigrade, (temperature of the bath,) taking care that themass is well stirred. The original stiff mixture when heated firstbecomes liquid and forms at about 200 centigrade a dry mass, which canbe easily pulverized to form a powder. At this stage the vessel isclosed. The temperature of the bath is kept for, say, two hours at 200centigrade. Subsequently it is raised to 240- centigrade, and heating atthis temperature is continued for about two hours, until test portionsof the melt dissolve in hot water with a reddish-violet color and theintensity of this color no longer increases. The product thus obtainedwhen cold. can be directly used for dyeing purposes. It forms a blackishpowdery mass, for the greatest part soluble in hot water, in hot dilutesoda-lye, in hot dilute sodium carbonate solution, and in concentratedsulfuric acid (66 Baum) with a reddish-violet color. From its solutionsin 8 water it is precipitated by the addition of dilute mineral acids,sulfureted hydrogen being set free at the same time. It dyes unmordantedcotton in boiling baths containing common salt and sodium carbonatebright o bluish-violet shades, which withstand the action of alkaliesand are sufficiently fast to the action of light.

The process proceeds in an analogous manner if in place of zinc chlorid,used in the 5 above example, other zinc compounds-such as zinc sulfate,zinc carbonate, zinc oxid, or the like, or metallic zinc itself,preferably in the form of zinc dust-are employed. The sodium sulfid andsulfur prescribed in the Ice above example can be replaced by otheralkaline sulfid-carrying compounds, such as sulfur and potassium sulfid,sulfur and soda, sulfur and potassa, sodium polysulfid, potassiumpolysulfid, or the like. A similar result is obtained if othernitroso-LS-dioxynaphthalenesulfo acids, such asnitroso-LS-dioxynaphthalenet-monosulfo acid or the like, are used inplace of nitroso-l. 8-dioxynaphthalene- ZA-disulfo acid. As abovementioned, the nitrosodioxynaphthalenesulfo -acids are by the reducingaction of the alkaline sulfidcarrying compounds first converted intoamido-LS-dioxyn aphthalenesulfo acids,which yield the final dyestuffs.The same effect is attained if azo dyestuffs of1.8-dioxynaphthalenesulfo acids, such as the coloring-matters obtainedby means of diazotized anilin, naphthylamin, or the like, are employed.In this case the azo dyestuffs used are by the action of the alkalinesulfid-carrying compounds first split, amido-1.8-dioxynaphthalenesulfoacids and anilin, naphtylamin, or the like being produced, so that theresulting amido-1.S-dioxynaphthalenesulfo acids yield by the furtheraction of the alkaline sulfidcarrying compounds and zinc the finisheddyestuffs, whereas the regenerated amido compounds volatilize or are notacted upon under the above conditions. The process is carried out in thesame manner if the complete amido-1.S-dioxynaphthalenesulfo acids areused. These amido acids can be obtained, for instance, by reducingnitroso-1.8-

dioxynaphthalenesult'o acids or the azo dyestufis resulting from thecombination of diazo compounds with 1.8 dioxynaphthalenesulfo acids.

Having now described my invention and in what manner the same is to beperformed, what I claim as new, and desire to secure by Letters Patent,is-

1. The process for the production of new dyes giving violet shades onunmordanted cotton which process consists in subjecting at elevatedtemperatures amido 1.8 dioxynaphthalenesulfo acids to the action of analkaline sulfid-carryin g compound and zinc which may be also employedin the form of a zinc compound substantially as described.

2. The process for producing a new dye giving bluish-violet shades inbaths containing common salt and sodium carbonate, which processconsists in subjecting at elevated temperatu res amido 1. 8dioxynaphthalene-Zetdisulfo acid to the action of alkaline sulfid,sulfur and zinc chloride substantially as described.

3. As new articles of manufacture the violet cotton-dyes obtainable fromamido-LS-dioxynaphthalenesulfo acids by the action of alkalinesulfid-carrying compounds and zinc which may be also employed in theform of a zinc compound at elevated temperatures, forming blackishpowdery masses, for the greatest part soluble in hot water, in hotdilute soda-lye, in hot dilute sodium carbonate solution and inconcentrated sulfuric acid (66 Baum) with a reddish-violet color, beingprecipitated from their solutions in water by the addition of mineralacids, sulfureted hydrogen being set free at the same time,

producing on unmordanted cotton in boiling baths containing common saltand sodium carbonate violet shades fast to the action of alkalies andsufficiently withstanding the action of light, substantially asdescribed.

4:. As a new article of manufacture the specific dye obtainable fromamido-1.8-dioxynaphthalene-2.4-disulfo acid by the action of alkalinesulfid-carrying compounds and zinc chloride at elevated temperaturesforming a blackish powdery mass, for the greatest part soluble in hotwater, in hot dilute soda-lye, in hot dilute sodium carbonate solutionand in concentrated sulfuric acid (66 Baum) with a reddish-violet color,being precipitated from its solution in water by the addition of mineralacids, sulfureted hydrogen being set free at the same time, dyeingunmordanted cotton in baths containing common salt and sodium carbonatebright bluish-violet shades fast to the action of alkalies andsuificiently withstanding the action of light, substantially asdescribed.

In testimony whereof I have signed my name in the presence of twosubscribing witnesses.

ROBERT DEMUTI-I.

Witnesses:

R. E. JAHN, O'rrro KoNIG.

